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Change to PC100 memory

I can't leave well enough alone.  Everything was working perfect until I upgraded from 64mb EDO ram total (2 @ 32mb simms) to 1 dimm 128mb PC100 8/10.  This change would not work with existing registry.  All kinds of vxd errors.  Tried to reload win95b in another directory, but problems persisted.  After several attempts to reinstall win95b, each time going through scandisc and finding new problems with cross links, the system now does not want to recognize the hard drive.  It gives an INT24 error.  

  Q1  Is there any patches required for win95b to function properly with PC100 memory?

  Q2  The mainboard includes settings for PC100 at 6,7 or 8ns, and describes that it will work with PC100 at 10 and 12ns in another area of the manual, but does not specify settings.  Are the settings the same for this mainboard?

Q3  What method can be utilized to recover some of the data on the hdd before I resort to reformatting?

System is AMDK6-400-2, FIC 503+ mainboard with VIA chipset, UDMA 7gb udma hdd, win 95b.

Thank You
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lexus
Asked:
lexus
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1 Solution
 
kschangCommented:
A1: No there is not. Memory speed is a HARDWARE issue, not software.

A2: Huh?

A3: Put the HD on another computer that IS working and run SCANDISK on that.

Suggestion 1: You DO have the AMD "speed" patch for WIN95, right? That cures some initial startup problems that's speed related.

Suggestion 2: Try SLOW DOWN the mainboard. See if it's stable at 66 MHz bus speed. If it IS stable, you got cheated on the memory.

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chewymonCommented:
T recover the data, reinstall the EDO memory and backup.  The problem you are experiencing might be the motherboard.  The board I am using supports EDO and PCI memory.  However, the largest capacity DIMM it will recognize is 64MB.  Are you sure your board supports a single 128 DIMM?
 
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lexusAuthor Commented:
I do have the K62update and have slowed the mainboard to 300 during install.  I have been through that problem before.

The mainboard manual claims it will work with two 256mb dimms for a total of 512mb.

The memory is from Frys and the package says 8 or 10ns.  How can you check the memory?  The start up bios check says it's ok.

I have moved the hdd to another computer, and it too does not recognize it.  Something about invalid media, INT24.  It won't allow a scan or chkdisk.  The bios does recognize it, and autoselect gives the same heads/cyl/etc configuration as I have always used.  It appears the FAT32 is confused.

I even reformated an old 250mb drive (after removing a layer of dust), loaded w95b and my CDRW software to see if I could read the drive and transfer (backup) the data to CDRW.  No avail.  (The memory hasn't seemed to be a problem though.)  Is it normal that win95b registry has memory information in it that reguards PC100 different then std EDO or FPM?  I have changed out many computers' memory before without any failure.  (Only times where it wouldn't work when the bios required 36 bit error checking vs 32 bit.

Any ideas?

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kschangCommented:
Sounds like your registry is complete f**ked, IMHO. Consider reinstall?
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lexusAuthor Commented:
How can a retreive the data on the drive before I reformat when I can't read it?
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kschangCommented:
You said you slowed the system down to 300. What's the FSB speed then? Would that be 66? Just wondering.
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lexusAuthor Commented:
No, still 100.

Will spinrite 5.0 work in this case?
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oldgreyguyCommented:
THE MEMORY IS FROM FRY'S....................aaargh!!!

I will buy you a beer if that memory is good. Go to:

www.crucial.com and get your memory


good luck, bill
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cumboCommented:
Are you running both the EDO and PC100 at the same time?

FIC motherboards don't like that configuration..

Cumbo
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rhomulosCommented:
Although I don't know fry's I do know that using Cheap RAM is never worth the money you save.  All RAM's do not lead to working computer.
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jhanceCommented:
You memory module is either faulty or not fast enough to run at 100MHz bus speed.  Contrary to popular belief, true PC100 RAM is rated at 7.5nS or faster!  Many slimy operators are selling 8 and even 10nS rated RAMS that appear to work fine at 100MHz.  The problem is that they are generally unreliable.  In my experience, Fry's is usually reliable so it's very possible you just have a bad module, it happens...

The BIOS POST test is not a good indicator of good memory.  If a RAM fails the POST testing, it's certainly bad.  If it passes, it may be bad.  Problems like you describe are a good indication that the RAM is bad.  Get a replacement and try again.  
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lexusAuthor Commented:
I am only running the single 128mb PC100 DIMM.

I will exchange the RAM to see if this solves the main problem, but how can I recover some of the data on the hdd before I resort to reformatting?

Is there a program that accurately tests RAM modules?
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jhanceCommented:
After you get your hardware working OK, I'd suggest something like Norton Disk Doctor (or similar) to try and recover your drive.  It's possible that just the partition table is messed up.

In my opinion, it's not possible to accurately test RAM modules with software.  Even the small desktop RAM tester boxes are of limited value.  They just cannot measure the true speed of something so fast.  PC100 RAM must deliver data to it's outputs withing 7.5nS.  If it takes 8nS, then it's not PC100.  It takes expensive HARDWARE to measure the difference between 7.5 - 8 nS.
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lexusAuthor Commented:
jhance,
Is it normal that changes in RAM effect the registry?  What does INT24 refer to?  If the RAM is not really PC-100 (ie 10ns) should the mainboard jumbers still be set for PC-100 memory or standard 66?  I thought that PC-100 memory allows for 50% faster (66mhz vs 100mhz) throughput due to a faster (wider) bus from CPU to Memory, and the specific speed of the memory is not the critical issue.  If memory speed is so critical, how come a change from 60/70ns memory to 10ns doesn't speed things up 6 fold?
Thanks for your help.
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jhanceCommented:
If the RAM is bad, the registry can very easily be corrupted.  If the RAM is not PC-100 it should still run at 66MHz memory bus speed.  But I thought you had said you did that already????  Again, it's still possible that the RAM is just bad at any speed.

As far as the 66 vs. 100MHz and the 60/70nS vs. 10nS, you're comparing apples and oranges.  The new types of memory, specifically SDRAM are rated differently that the old kinds.  Today, virutually all RAM sold in the DIMM format are SDRAM vs. the older EDO types.  EDO and other older memories were rated in access time and the last generation was 60nS or so.  These ran in systems with memory busses up to 66MHz.  At 66MHz, however, a memory bus cycle takes 15nS so there is a difference of about 45nS between the bus cycle and the memory speed.  What makes up the difference?  The dreaded WAIT STATE!!  In this example, the CPU will be forced to add 3 WAIT STATES to EACH memory cycle.

Recognizing this as a big performance killer, RAM designers came up with the SDRAM scheme.  In this case, the SDRAM is able to deliver consecutive memory locations at a much faster rate than random locations.  It relies on the fact that most of the memory locations that a CPU accesses are in fact sequential.  As long as the CPU reads data in order, things happen quickly.  If the program jumps off track, then it takes a few wait states to make it up.  At 66MHz memory bus, a 10nS SDRAM can deliver a data location every 10nS.  At 100MHz, a 7.5nS SDRAM can deliver one every 7.5nS.  

You might ask, "my calculations show that 100MHz corresponds to a 10nS cycle time. You know 1/100MHz = 10nS.  Why won't 10nS SDRAMS work?"  It's a good question.  Remember, we are dealing with real world electronics and nothing happens on 0 time.  It takes some finite amount of time for the SDRAM output signal to propogate through the circuit board traces and make it's way into the pins of the CPU.  The PC100 spec allows 2.5nS for this time(10nS - 7.5nS = 2.5nS), so the SDRAM must be faster than the memory bus cycle time.

Going from EDO at 60/70nS to SDRAM at 10 or 7.5nS doesn't speed up things by 6X since you don't get pure sequential memory access in practice.  The speedup is significant, however, and is usually on the order or 2-3X.  If you look at memory bandwidth results from an SDRAM vs. an EDO system, you will see this.  Your mileage may vary, however, as memory bandwidth is just one of many factors that affect the overall performance of a PC running application software.
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lexusAuthor Commented:
Took back the memory and bought a module from another dealer.  Reloaded Win95b.  Everything is ok now ...... except whenever I try to install the VIA UDMA drivers, the unit does not recognize the CD drives, and the Bus Mastering is (?) in the system device manager.  Without the UDMA everything is fine.  I guess I'll ask this question seperately.
Thanks for all the fine information on memory.
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